Summon feature acting up

I started to try out the Summon feature yesterday in a parking lot. I turned it on via my phone app and then held the reverse button on the app. However, it would move 5 feet and then stop with a message saying the app is having trouble connecting with the car. This happened 3-4 times.

Has anyone experienced this? Any idea why this would be happening. I set the bumper distance as 20 inch and the overall at 40 feet. Not sure if that matters though.